Topeak  PanoBike  Heart Rate  Monitor Transmission Range: 50+ft Tech Bluetooth Smart super low energy technology; Battery Lifetime 1800 hours Open API allows to work with PanoBike App and other Apps with Bluetooth 4.0 connection program; IPX 7 waterproof rating Weight 32 g/1.13 oz. (strap). 14 g/0.49 oz. (monitor) Compact, low profile heart rate monitor with soft fabric chest strap molds to your body shape and allows comfortable, full range of motion Unique Bluetooth Smart algorithm extends battery lifetime up to incredible 1800 hours (5 yrs. lifetime if workout 1 hour per day)